Sources & methodology
Trace the information. Inspect the calculation. Check what is still an assumption.
How information is sourced
Trade and tax guidance is linked to HMRC and GOV.UK. Incoterms explanations are linked to ICC material. Carrier examples identify the carrier and never become universal pricing rules.
Transport guidance is not limited to air freight. ShipTally treats road, sea, air, rail, courier and multimodal movements separately where the source or method changes.
What a review date means
A review date records when the cited guidance was checked for this release. It is not a guarantee that the rule applies to your shipment or that the source has not changed since. Source publication and effective dates are distinct from our review date.
Rates and unknown information
Live Tariff Intelligence queries HMRC’s managed Trade Tariff API using server-side OAuth credentials. It can surface live commodity records and measures for the selected service, date and origin. ShipTally does not silently convert a returned preferential, quota or conditional measure into the rate you should declare: the user must verify the conditions and choose the rate they are relying on. Other calculators still accept user-confirmed rates where live tariff data has not been carried in. Blank optional amounts are excluded from arithmetic and listed as NOT SUPPLIED. Zero is an explicit input, not a conclusion reached by the tool.
Live Tariff methodology
- Classification: HMRC classification search returns a shortlist of tariff candidates. ShipTally labels the search score as a relative match only; it is not a probability that the code is correct.
- Verification: declarable 10-digit codes are checked against the live commodity record. Users should compare the hierarchy and legal tariff wording where classification turns on product facts.
- Measures: origin/date filtered import or export measures are shown with rates, geographical scope, conditions, quota references and additional codes where returned.
- Preference: an origin scheme being available does not prove the goods qualify. Product-specific origin rules and proof of origin must still be checked.
- Costing hand-off: ShipTally only carries a selected percentage rate into costing. Conditional rates require an explicit user confirmation before hand-off.
Calculation methods
- Profit: one-product import and resale scenario; recoverable import VAT excluded from cost, with separate border and VAT-return cash flow.
- Valuation: user-selected additions and deductions. Unresolved adjustments remain outside the arithmetic and are flagged.
- Allocation: largest-remainder integer-penny method, applied separately to each shipment charge.
- Invoice checks: completeness prompts and arithmetic checks, not authentication or customs approval.
Corrections
Record the page address, result reference, issue and relevant official source. Remove commercially sensitive details before sharing. Check the contact page for the configured correction route.
Source register
HMRC — managed Trade Tariff API & Developer Portal
Live commodity records and measures are requested from HMRC’s managed API using OAuth 2.0 client credentials. Classification workflow follows HMRC’s published tariff tooling approach: shortlist candidates, inspect hierarchy/notes and verify the code rather than treating semantic rank as certainty. API documentation · Developer Portal
LAST REVIEWED / 03 OCT 2026
HMRC — transaction value
Conditions, additions and deductions under Method 1. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — valuation methods
Method selection; the workbench does not choose a method. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — import VAT value
VAT value and incidental expenses. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — postponed VAT accounting
Eligibility and written instructions. Read source
LAST REVIEWED / 03 OCT 2026
ICC — Incoterms® 2020: eleven rules
Current 2020 edition; seven any-mode rules and four sea/inland-waterway rules. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — appointing an intermediary
Information, authority and due diligence. Read source
LAST REVIEWED / 03 OCT 2026
GOV.UK — import step by step
Import preparation and route-specific guidance. Read source
LAST REVIEWED / 03 OCT 2026
GOV.UK — export step by step
Export preparation and records. Read source
LAST REVIEWED / 03 OCT 2026
GOV.UK — invoice information
General invoice requirements; not a universal customs checklist. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — direct overseas sales
Low-value direct sales and exceptions. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — overseas marketplace sales
Marketplace VAT treatment. Read source
LAST REVIEWED / 03 OCT 2026
HMRC — delivery costs
Border freight, insurance and identifiable UK charges. Read source
LAST REVIEWED / 03 OCT 2026
DHL — weight and dimensions
Carrier-specific volumetric-weight explanation; verify your own service. Read source
LAST REVIEWED / 03 OCT 2026
GOV.UK — Customs valuation: Incoterms
UK government summary of current Incoterms terms and transport groups. Read source
LAST REVIEWED / 03 OCT 2026
GOV.UK — Making a full export declaration
Mode-specific declaration timing for road/inland waters, sea, air and rail; always recheck before departure. Read source
LAST REVIEWED / 03 OCT 2026